The benefits of serverless vs infrastructure in a data center. No infrastructure management, no patching, etc.
The cost benefit. Pay only when code is being executed. With the free tier, this code execution is free!
The reliability and scalability. Code will execute in any AZ and can execute concurrently. No bottlenecks.
You choose your programming language
Code can be invoked by any event. Files landing in storage, alexa skill, the completion of other business logic, etc.